Just bought a used YBA-200-2 about a month ago. The -2 designation denotes the 2nd iteration of the amp. The straight YBA-200 had auto-bias (and 6550's as outputs), but the auto-bias was causing problems, so Traynor re-designed the amp by taking out the auto-bias circuitry and switched to KT88's as output tubes.
If you search that amp model, you will find that some have had their version 1 amps modified to be a version 2 amp. Also, for those who do not want the somewhat early break-up that is a characteristic of this amp, you can change one or both of the 12AX7's in the pre-amp to 12AT7's for cleaner headroom.
Other than the auto-bias problem with the first version, Traynor makes very solid, reliable equipment. And from their website you can download full schematics if service is needed down the road.
As to versatility, some have written how they don't really like the EQ section of the amp - mainly the "Scoop" controls, and that the tone is somewhat bright. It is a passive tone stack, so better to crank bass/treble/mids full up (in effect, zero attenuation) and then turn down (attenuate) what you don't want.
I don't find it too hard to get out of it what I want, but I am not a gigging bassist (yet), so have very limited experience with all the variables different venues can throw at you.
Anyway, that's my limited knowledge in a nutshell.
If you really want headroom, go for the YBA-300. Better EQ section, too. Just more money, about $1500 new and harder to find used ones.
- Squier Owners Club - Ampeg Owners Club #905 - Fender Precision Bass Club #993 -